Gas Exchange
Topic 6.4.1
Topic 6.4.2
Why do we need a ventilation system?
We are large organisms. Oxygen cannot diffuse into all our
cells directly from the air, nor can waste products be directly
ejected from the body. We have specialized organ systems,
which are efficient, but need delivery of nutrients and
removal of waste. The ventilation system ensures the blood
can be the medium for this.
We are land-borne. Gases need moist surfaces (membranes) in
order to diffuse. Our lungs are moist membranes, allowing
oxygen to diffuse into the blood and carbon dioxide
to diffuse out.
The ventilation system maintains a large
concentration gradient between the alveoli and
the blood. The constant flow of blood past the alveoli brings
blood with a high CO2 concentration and low O2
concentration. Breathing out keeps the CO2 concentration
in the alveoli low, so it diffuses out of the blood.
Breathing in keeps O2 concentration in the alveoli high,
so it diffuses into the blood.
Topic 6.4.2
Diagram from: http://www.sciencequiz.net/jcscience/jcbiology/gapfilling/breathingsystem.htm
Topic 6.4.4
Topic 6.4.5
Data Analysis – What does this tidal volume graph tell you about the process of breathing?
See what inferences
you can make with
regard to –
Amount of air taken
in in the average
breath
Amount of air pushed
out.
Maximum capacity of
the lung
Key –
Tidal Volume – regular breathing
changes
Inspiratory Reserve – amount a deep
breath can intake
Expiratory reserve – amount a heavy
exhale can emit
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter25/animation__gas
_exchange_during_respiration.html
Topic 6.4.2
http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP15104
Topic 6.4.3
Transport across the alveolar membrane is assisted by two different types of cells, known as
pneumocytes.
Diagram
Type I Pneumocytes
Type II Pneumocytes
Extremely Thin,
Adapted to carry out
gas exchange
Secrete a solution
containing surfactant
that creates a moist
environment to
prevent the sides of
the alveolus to adhere
to each other by
reducing surface
tension.
Light Micrograph
Which process(es) of membrane transport are being used in
gas exchange at the membranes of the alveoli?
Topic 6.4.3
http://www.footprints-science.co.uk/alveoli.htm
Topic 6.4.3
Many major lung diseases are caused by a malfunctioning protein and/or structure within the
gas exchange pathway.
Research the causes and consequences of the following diseases:
Tuberculosis
Causes
Consequences
Lung Cancer
Emphysema
Cystic Fibrosis
Your Task – To create a life size model of the body
over the course of the Human Physiology Unit
Circulatory Section–
Materials : Large Poster Paper
Construction Paper
Scissors
Tape
Markers
Steps –
1. Cut out and label a respiratory system and put it
on the body in the correct positioning.
2. You must include all of the macro structures
(Sinus Cavity, Lungs, Trachea, Bronchii,
Bronchioles, Alveoli) with one lung cut so that
you can see the internal structures.
3. Make one bundle of Alveoli surrounded with the
capillaries, and highlight the type 1 and 2
pneumocytes within. Try to connect the heart
with a vessel coming from the Right Ventricle of
the heart, and returning to the Left Atrium.
Carbon Monoxide Poisoning – the
silent killer (CO)
What is occurring in this graph as a
result of prolonged exposure to CO?
Breathing Exercises – desk yoga
(it’s IB after all, let’s bust some stress)
1. Simple exercises. Keep your neck straight.
• Rotate shoulders forwards, then backwards, 5 times each.
• Bend your neck to touch your head to your shoulder, left then right, 5 times each.
• Tilt your head forward, touching chest, then backward, 5 times each.
2. Breathing observation
• Close your eyes, breathe normally.
• “Observe” the breathing process.
3. Pranayama
• Stand up.
• Take gentle, deep breaths.
• Feel the air moving in and out, trying to control its flow.
• Think happy thoughts about graduation.
Breathing exercises from: http://www.healthandyoga.com/html/news/exercise.html
Image: '11,750 Foot Yoga Moment'
http://www.flickr.com/photos/94833286@N00/2838289483 Found on flickrcc.net